This application claims the priority of German Application No. 198 21 803.6, filed May 15, 1998, the disclosure of which is expressly incorporated by reference herein.
The invention relates to a method and arrangement for controlling the longitudinal velocity of a motor vehicle. By means of corresponding devices, the vehicle position is determined and a desired velocity defining value and/or a velocity defining limit value is indicated as a function of the determined vehicle position for the longitudinal velocity control. In the present case, the term "control", is used broadly to also include automatic controls.
Methods and arrangements of this type are known in various embodiments. Thus, in the case of a system disclosed in International Published Patent Application WO 88/05199, in addition to geographical data of an electronic road map, safety-relevant data, which, among other things, are also relevant to the control of the longitudinal velocity, are previously stored and are retrieved when driving on the corresponding route sections. In the case of systems as described in German Published Patent Applications DE 42 01 142 A1, DE 195 02 954 A1 and International Published Patent Application WO 93/17406, as well as German Patent Document DE 195 06 364 C2, desired velocity value and/or velocity limit value data relevant to the longitudinal velocity control are determined from the geometrical data of a digitally stored road system map. In particular, it is suggested in the above-mentioned German Patent Document DE 195 02 954 A1 to determine and store specific route-dependent characteristic values concerning the course of the route, such as turns, radii of turns and yaw angle values, when driving a route for the first time which will be subsequently traveled frequently. In the case of an active automatic velocity control, the driver must then define a first desired velocity value and, by means of the stored characteristic values, the system will determine a pertaining second desired velocity value which is compared with the first. Based on the comparison, the lower of the two will be used as the actual desired velocity value.
From German Patent Document DE 34 38 385 C2 and European Patent Document EP 0 188 455 B1, systems are known in which such longitudinal-velocity-relevant data, particularly with respect to defining velocity limit values, can be indicated by storage units arranged on the route-side and can be read by corresponding vehicle-side read units. Another system of this type is disclosed in German Published Patent Application DE 33 08 803 A1, where, in addition, a vehicle-specific coded identification card is provided. The various driving conditions of the motor vehicle can be programmed into the card in a free or fixed manner, such as a maximal driving speed or a maximal longitudinal or lateral acceleration. This is to have the effect that, among other things, the maximum possible driving speed can be adapted to the external conditions and to the driver's driving capability.
German Patent Document DE 38 17 495 C2 discloses a system in which data relative to the respective user with respect to electronically controllable functions of a motor vehicle are stored in a retrievable manner in user-individually assigned storage units. To the extent that the electronically controllable functions concern those for a transmission line and therefore longitudinal-velocity-relevant functions, it is suggested that the respective vehicle handling of the concerned user be continuously monitored, be assigned to one of several definable vehicle handling categories, and that the assignment to the respective category be stored. The storage units can be housed in user-side electronic key units which are part of the vehicle.
The invention is based on the technical problem of providing a method and arrangement of the above-mentioned type which permit an advantageous new longitudinal velocity control, particularly for repeatedly driven routes.
The invention solves this problem by providing a method for controlling the longitudinal velocity of a motor vehicle, wherein the vehicle position is determined and a desired velocity defining value and/or a velocity defining limit value is defined for controlling the longitudinal vehicle velocity as a function of the determined vehicle position. Velocity data are detected by way of the actual value and/or a set desired value and/or a set limit value of the vehicle longitudinal velocity as a function of the vehicle position. The desired velocity defining value and/or velocity defining limit value is determined from the velocity data detected for the respective vehicle position during one or several preceding drives. The detected velocity data themselves and/or the data concerning the desired velocity defining value and/or velocity defining limit value determined therefrom are stored in a retrievable manner. An arrangement for solving the prior art problems controls the longitudinal velocity of the motor vehicle and includes vehicle position determining devices, and longitudinal velocity control devices for controlling the longitudinal velocity of the vehicle according to a desired velocity defining value and/or velocity defining limit value defined as a function of the vehicle position. The longitudinal velocity control devices comprise velocity defining devices which detect velocity data by way of the actual value and/or a set desired value and/or a set limit value of the longitudinal velocity as a function of the vehicle position and determine the desired velocity defining value and/or the velocity defining limit value from the velocity data detected for the respective vehicle position during one or several preceding drives. The velocity defining devices contain storage devices for storing the detected velocity data themselves and/or the desired defining value data or defining limit value data determined therefrom.
In the case of the method according to the invention, velocity data are detected in the continuous driving operation by way of the actual value and/or a set desired value and/or a set limit value of the longitudinal vehicle velocity as a function of the vehicle position, and the desired defining value and/or the defining limit value for the longitudinal velocity control is determined from the velocity data recorded for the respective vehicle position during one or several previous drives. The arrangement according to the invention is suitable for implementing this method.
In a memory-type manner, this approach utilizes the actual velocity selected by the driver in the past on a respective route section and/or the desired velocity and/or the limit velocity, while storing this information, for deriving and defining a suitable desired value and/or limit value for the longitudinal velocity control when again driving on the concerned route section. The individual devices used for this purpose are familiar as such to a person skilled in the art, for example, from conventional navigation and range control systems, particularly suitable vehicle position determining devices, longitudinal velocity control devices, such as those which automatically intervene in the transmission line and/or the braking system, and data storage devices for recording relevant data. Characteristically, correspondingly designed defining devices are provided which obtain from the detected velocity data the desired velocity defining value and/or the velocity defining limit value for the respectively just driven route section and indicate this value to the velocity control devices, at least in the form of corresponding information for the vehicle driver and preferably in the form of desired-value signals or limit signals which are fed directly to a device for the automatic longitudinal velocity control. By means of such an automatic control device, a memory-aided longitudinal velocity control can be implemented which is largely independent of the vehicle driver. The limit value or desired value changes occurring when the stored data are retrieved can be indicated to the driver by suitable visual, haptic or acoustic devices.
In a preferred embodiment of the method, the storing of the velocity data and the indicating of the desired velocity defining value and/or of the velocity defining limit value takes place as a function of one or several different velocity influencing variables continuously sensed during the drive. Such variable influences are, for example, the speed of the traffic driving ahead, the weather, changing traffic signs and light signal systems. By taking into account these influential variables avoids the situation where indication of the desired velocity defining value and/or of the velocity defining limit value during a drive takes place by means of velocity data which were recorded previously during a drive under completely different conditions. On the contrary, the data are then used in a targeted manner for this purpose which were previously recorded under the same or at least largely the same conditions.
A system further developed according to the invention is suitable for implementing this method, for the purpose of which it particularly contains the required sensor devices for detecting the influential velocity variables taken into account.
In the case of a further preferred method, a first special type of defining the desired velocity defining value and/or the velocity limit value is provided. Here, an actual velocity value or a desired velocity value or a velocity limit value are used, as detected during an earlier drive for the corresponding vehicle position, in a driver-commanded manner; that is, upon a corresponding triggering command by the vehicle driver. An arrangement further developed according to the invention is suitable for implementing this method, in that its defining devices are designed correspondingly.
A method further developed according to the invention contains a second advantageous manner of defining the desired velocity defining value and/or the velocity defining limit value by utilizing the actual velocity value last driven at the corresponding point or the adjusted desired velocity value or velocity limit value. An arrangement further developed according to the invention by means of a corresponding system design is suitable for implementing this method.
A method further developed according to the invention contains a third advantageous manner of defining the desired velocity defining value. Here, the actual velocity value is used which last existed at the respective point when driving on a free road; that is, without any influence on the longitudinal velocity by a vehicle driving ahead, for example, within the scope of a ranging control, whether because of an automatic velocity control phase or by a defining of the velocity by the driver. For this purpose, the criterion of a free-road drive is appropriately detected, for example, by detecting and evaluating the distance to the vehicle driving ahead while the driving velocity is known. An arrangement further developed according to the invention, which, particularly for this purpose, has devices for recognizing the condition of a free-road drive, is suitable for implementing this method.
In the case of a method further developed according to the invention, it is provided as another advantageous possibility to determine the desired velocity defining value or velocity defining limit value as a selectable percentage value from several values of the actual velocity detected during preceding drives or from the desired velocity or the limit velocity. Here, the actual or desired or limit velocity values of all preceding drives or classified according to the mentioned different influential velocity variables, are taken into account, particularly regarding the existence of the condition of a free-road drive. For implementing this method, an arrangement further developed according to the invention is suitable, for the purpose of which particularly its defining devices are designed appropriately.
In the case of a further preferred method according to the invention, for route sections for which there are not yet any evaluatable velocity data of a previous drive, the desired velocity defining value and/or velocity defining limit value are derived from desired velocity or limit velocity defining data stored beforehand for the considered road network, specifically for the route, or are derived implicitly from the geometrical data of a stored road network itself. As a result, also for the case of a first-time driving of a route section, a useful desired value or limit value definition can be provided for the longitudinal velocity control. For implementing this method, an arrangement is suitable which is further developed according to the invention and which, for this purpose, contains velocity data and road network data which, in a particularly suitable manner, were stored beforehand in storage devices.
In another preferred method according to the invention, it is possible to provide for a respective vehicle position several parallel rough defining values from velocity data detected during previous drives and optionally velocity data explicitly filed beforehand relative to the route or implicitly determined from geometrical road network data. From these, according to a definable priority list the respective highest-priority existing rough value is selected as the desired velocity defining value or speed defining limit value. For implementing this method, an arrangement further developed according to the invention is suitable, for the purpose of which particularly its defining devices have a suitable design.
In yet another preferred method according to the invention, a driver-specific or transferrable selection of the route-dependent desired velocity defining value or velocity defining limit value is provided. This is done so that a velocity profile for the longitudinal vehicle velocity which is specific to each driver of a vehicle or can be transferred to various vehicles is available for each driver of a vehicle. For implementing this method, an arrangement is suitable which is further developed according to the invention and which, for this purpose, has storage areas or storage units which are separate with respect to the driver and arranged on the vehicle side or, as an alternative, driver-side storage units which are housed in electronic keys or the like or storage units outside the vehicle which can be used in different vehicles.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.